OUTFLOW STRUCTURE OF THE QUIET SUN CORONA PROBED BY SPACECRAFT RADIO SCINTILLATIONS IN STRONG SCATTERING
OUTFLOW STRUCTURE OF THE QUIET SUN CORONA PROBED BY SPACECRAFT RADIO SCINTILLATIONS IN STRONG SCATTERING
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DOI：
10.1088/0004-637x/788/2/117
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发表时间：
2014-05
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通讯作者：
T. Imamura;M. Tokumaru;H. Isobe;D. Shiota;H. Ando;M. Miyamoto;T. Toda;B. Häusler;M. Pätzold;A. Nabatov;A. Asai;K. Yaji;M. Yamada;M. Nakamura
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作者：
T. Imamura;M. Tokumaru;H. Isobe;D. Shiota;H. Ando;M. Miyamoto;T. Toda;B. Häusler;M. Pätzold;A. Nabatov;A. Asai;K. Yaji;M. Yamada;M. Nakamura
无线电闪烁观测无法探测无线电波散射极其强烈的低日冕中的流速。在这里，我们使用 Akatsuki 航天器作为射电源，首次将强散射理论应用于射电闪烁，连续估计从太阳附近到外日冕（日心距离为 1.5-20.5 个太阳半径）的流出速度。在安静的太阳低日冕中，在很宽的纬度范围内观察到小的、非零的流出速度，这表明从闭环到太阳风的等离子体供应发生在一个扩展的区域。有人提出，存在低至 100 m 尺度的幂律密度涨落，这表明存在发达的湍流，而湍流在日冕加热过程中发挥着关键作用。在较高海拔处，观察到径向开放场典型的快速加速，并且从速度分布得出的温度在外日冕中显示出明显的最大值。这项研究开辟了从大量现有行星际闪烁数据中观察太阳附近详细流动结构的可能性。
Radio scintillation observations have been unable to probe flow speeds in the low corona where the scattering of radio waves is exceedingly strong. Here we estimate outflow speeds continuously from the vicinity of the Sun to the outer corona (heliocentric distances of 1.5–20.5 solar radii) by applying the strong scattering theory to radio scintillations for the first time, using the Akatsuki spacecraft as the radio source. Small, nonzero outflow speeds were observed over a wide latitudinal range in the quiet-Sun low corona, suggesting that the supply of plasma from closed loops to the solar wind occurs over an extended area. The existence of power-law density fluctuations down to the scale of 100 m was suggested, which is indicative of well-developed turbulence which can play a key role in heating the corona. At higher altitudes, a rapid acceleration typical of radial open fields is observed, and the temperatures derived from the speed profile show a distinct maximum in the outer corona. This study opened up a possibility of observing detailed flow structures near the Sun from a vast amount of existing interplanetary scintillation data.